1. Field of the Invention
The present invention generally relates to medical apparatus and methods for valve removal from a patient. More particularly, the invention relates to an endoluminal catheter and methods for removing a defective valve and adapted for implantation of a valvular prosthesis.
2. Description of the Related Art
A valve in a body circulation system is to ensure unidirectional blood flow. When a valve is defective, a person feels weak and appears difficult to handle route physical workload or exercise. A defective valve may include a stenotic valve that can't open completely, a valve unable to close completely leading to regurgitation of blood back through the valve, or an infected valve. Other conditions leading to a defective valve may include changes in valve structure, rheumatic fever or other unknown reasons.
Defective cardiac valves have been routinely treated using an open-chest surgery for repair or replacement of aortic, mitral and other heart valves. Valves that are heavily calcified or significantly compromised by disease may need to be replaced. These procedures typically involve a full sternotomy and quadrangular resection of the anterior leaflet, while on cardiopulmonary bypass.
One emerging technique for valve replacement is a minimally invasive endoluminal procedure. This may be performed by a catheter-based percutaneous, endoscopic, or laparoscopic procedure. Before a valvular prosthesis can be implanted, the whole valve, including the valve base and its associated valve leaflets need to be removed from a patient.
Certain conventional surgical endoscopic, and laparoscopic procedures utilize staples or clips for repair of incisions or wounds, implantation of prostheses, anastomoses and the like. For example, surgical staples have been disclosed comprising angled and arcuate central and leg regions which can be flattened by a stapling tool having an anvil and driving structure. One such staple has been disclosed with side portions curved substantially in the form of an arc of a circle to prevent tearing of tissue by producing puncture channels.
Various forms of stapling tools have been disclosed. One such surgical instrument consists of an anvil adapted to lie flush with the skin, a cartridge containing a plurality of staples and a U-shaped pusher for bending the staples around the anvil. Such instruments typically have mechanical actuators within a handle mechanism for positioning the staples and activating the driver or pusher against the staple and anvil.
Laparoscopic procedures have also used staples, balloons and clip appliers or staple guns for procedures such as cholecystostomies, ligation and hernia repair. Laufer et al. in U.S. Pat. No. 6,149,660 discloses such systems for intraluminally repairing blood vessels of vein valves. The Laufer et al. patent discloses the minimally invasive system for intraluminal repair of a body organ, lumen or cavity, for example, a blood vessel or a vein valve, using a catheter based system for deploying a bendable clip appliance, the entire contents of which are incorporated herein by reference.
Kuehn et al. in U.S. Pat. No. 6,165,183 discloses a leaflet fastener applicator generally has a size allowing insertion through a catheter and is capable of holding portions of opposing heart valve leaflets. Kuehn et al. also refers to a valve repair technique of an edge-to-edge suturing of the mitral leaflets, commonly referred to as a “bow-tie” repair. The bow-tie repair generally involves the use of a centrally located suture, although a suture can be placed close to a commissure, or multiple sutures can be used to complete the repair. A centrally placed suture creates a double orifice valve, which resembles a bow-tie. The entire contents of Kuehn et al. patent are incorporated herein by reference.
Williamson, IV et al. in U.S. Pat. No. 6,162,233 discloses wire fasteners having legs with lengths that are used to secure items, such as prosthesis valves to a patient during minimally invasive surgery. The fasteners are manipulated, tensioned and formed from the leg end of the fasteners and tools for initially placing the fasteners and for immobilizing, tensioning, cutting and bending the fasteners legs are disclosed. The entire contents of Williamson, IV et al. patent are incorporated herein by reference.
Stevens et al. in U.S. Pat. No. 6,125,852 and Donlon et al. in U.S. Pat. No. 6,010,531 disclose a minimally invasive device and methods for heart valve surgery, the entire contents of which are incorporated herein by reference. The surgical intervention may comprise replacing the cardiac valve with a prosthetic valve, wherein the native valve is removed using a tissue removal instrument.
Hamblin, Jr. et al. in U.S. Pat. No. 6,033,419 discloses an apparatus for cutting a heart valve annulus, the entire contents of which are incorporated herein by reference. The disadvantage of Hamblin, Jr. apparatus is that without immobilizing and stabilizing the valve leaflets, the apparatus may swing or float within the blood flow due to systolic and diastolic flows. Therefore, it is difficult to target the anatomic site of the valve structure remotely and cut the heart valve base effective for implantation of a prosthetic valve.
The above-mentioned patents disclose methods for fastening the leaflets or methods of removing a native valve using a tissue removal instrument, or methods for repairing a heart valve. However, no prior art has disclosed an endoluminal catheter generally having suitable dimensions for deployment and insertion into a human cardiovascular system in the vicinity of a defective valve by immobilizing the valve leaflets, separating a valve base of the defective valve, and removing said defective valve.
Therefore, it is an object of the present invention to overcome the disadvantages of the prior art and provide an improved apparatus and methods for removing a defective valve, wherein the removed annular space is suitable with implantation of a replacement valve.